Dissertations / Theses: 'Materials science as a profession'

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Biggers, Mandy Sue. "Elementary teachers' ideas about, planning for, and implementation of learner-directed and teacher-directed inquiry: a mixed methods study." Diss., University of Iowa, 2013. https://ir.uiowa.edu/etd/2438.

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Using a framework for variations of classroom inquiry (National Research Council [NRC], 2000, p. 29), this study explored 40 inservice elementary teachers' planning, modification, and enactment of kit-based science curriculum materials. As part of the study, a new observation protocol was modified from an existing protocol (Practices of Science Observation Protocol [P-SOP]) to measure the amount of teacher direction in science inquiry lessons (Practices of Science Observation Protocol + Directedness [P-SOPd]). An embedded mixed methods design was employed to investigate four questions: 1. How valid and reliable is the P-SOPd? 2. In what ways do inservice elementary teachers adapt existing elementary science curriculum materials across the inquiry continuum? 3. What is the relationship between the overall quality of inquiry and variations of inquiry in elementary teachers' enacted science instruction? 4. How do inservice elementary teachers' ideas about the inquiry continuum influence their adaptation of elementary science curriculum materials? Each teacher chose three lessons from a science unit for video-recorded observation, and submitted lesson plans for the three lessons. Lesson plans and videos were scored using the P-SOPd. The scores were also compared between the two protocols to determine if a correlation existed between the level of inquiry (measured on the P-SOP) and the amount of teacher direction (measured on the P-SOPd). Findings indicated no significant differences between planned and enacted lessons for the amount of teacher direction, but a correlation existed between the level of inquiry and the amount of teacher direction. In effect, the elementary teachers taught their science curriculum materials with a high level of fidelity for both the features of inquiry and the amount of teacher direction. A smaller group of three case study teachers were followed for the school year to give a more in-depth explanation of the quantitative findings. Case study findings revealed that the teachers' science instruction was teacher-directed while their conceptions of inquiry were student-directed. This study contributes to existing research on preservice teachers' learning about the continuum (Biggers & Forbes, 2012) and inservice teachers' ideas about the five features of inquiry (Biggers & Forbes, in press).

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Barker, Joanna. "Evaluating clinical competence in a health science profession." Thesis, Barker, Joanna (1987) Evaluating clinical competence in a health science profession. PhD thesis, Murdoch University, 1987. https://researchrepository.murdoch.edu.au/id/eprint/52158/.

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The evaluation tools at present in use to measure clinical competency, do not provide satisfactory validity, reliability, nor an appropriate level of standardisation. As clinical practice is a major component of an occupational therapy undergraduate degree programme, this population was used to investigate and to develop measurements of clinical competence and to provide a model for future use. The study explored the use of psychometric methods in the design of evaluation tools, measurement criteria and the steps required to develop evaluation tools for the clinical setting. Although the study had particular reference to Occupational Therapy, the model of clinical evaluation developed could be readily adapted for use with other clinical based health professional students. Following development and analysis, the tools were implemented on the study population of occupational therapists in two states. Western Australia and South Australia, over a four year period. The results indicated that the tools developed had reliability, content and concurrent validity for the population under study.

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Rose, Sharon L. "Isaac Asimov's Profession : a Burkeian criticism." Virtual Press, 1990. http://liblink.bsu.edu/uhtbin/catkey/722234.

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This is a rhetorical criticism of the science fiction short story, "Profession," by Isaac Asimov. Primary focus is on Asimov's persuasive use of this message to influence potentially creative young people to consider technological careers. A brief synopsis of the story is given, along with a statement of the functional role of science fiction in accustoming individuals to societal changes resulting from technological advancements.Methodology is based upon Kenneth Burke's dramatism which views human action in terms of a drama. Burke's concepts of identification and occupational psychosis are used in discovering the rhetor's use of persuasive strategies. Burke's pentad is used for analysis of significant ratios. The dominance of the act-scene ratio is demonstrated by the supremacy of action over motion.Asimov's work shows the influence of a philosophy of realism, identifiable by the featuring of the pentadic term "act." Asimov's primary motives are identified as a desire to share his belief in the benefits of technology and his own need for creative self-expression.
Department of Speech Communication

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Rigné, Eva Marie. "Profession, science and state : Psychology in Sweden 1968-1990." Doctoral thesis, Sociologiska institutionen, Göteborgs universitet, Göteborg, Sweden, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-51556.

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This dissertation consists of a case study of Swedish psychology during a specific period of time. It focuses psychology as a scientific discpline, as a professionalised occupation and as a cognitive resource for policy-making. From a general science studies perspective, it aims to provide a sociological and historical analysis of the development of psychological research, psychological practice and psychology's relation to social policy-making in key areas of the welfare state in general. The case study utilises discourse analysis, analysis of archival and documentary material, interviews and bibliometric analyses. It is argued that psychologists have changed their image from being primarily academics to being clinical practitioners whose expertise has moved from differential diagnostics to psychotherapy. Professional discourse has evolved similarly to that shown to be the case in other countries, drawing extensively on rhetorics of economics, humanitarianism and facilitation and control. A critical assessment of discourse analysis and constructionism is provided, arguing for a restricted application of constructionism in science studies. Further, professional action and organisation is analysed. It is argued that the professional project pursued by psychologists is characterised by power struggles within the profession, and is an outcome of adaptation to institutional demands stemming from the labour-market. It results in a pattern of professionalisation which deviates from what is hypothesised by much professionalisation theory. Psychology's role as a cognitive resource for social policy-making is analysed in relation to claims to decisive influence made by psychologists. It is argued that psychology has played a negligible role in key areas of policy-making. The case illustrates the politicisation of science rather than the scientization of policy-making. Finally, psychology's development as a a discipline is analysed. It is argued that the changes in the system of research and higher education illustrates the increasing influence of non-cognitive factors on disciplinary development. It has provided academic psychology with potential for growth but at the same time weakened its disciplinary core. Academic psychology has been more theoretically and methodologically diverse than is usually claimed, but a rivalling knowledge ideal to the traditional academic one has been introduced by sectorial research policy.

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Rigné, E. M. "Profession, science and State : psychology in Sweden, 1968-1990 /." Göteborg : Göteborg university, 2002. http://catalogue.bnf.fr/ark:/12148/cb39070067b.

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Nyström, Alexandra, and Felix Dürango. "Optimization of Assembly Material Feeding : at Electrolux Professional AB." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-42325.

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Electrolux Professional AB is a multinational industrial appliance manufacturer and among many other things one of the leading global providers of laundry solutions in Ljungby, Sweden. Electrolux, being a global company with millions of customers, are always striving for the most efficient way of work in order to reach the best results. The ambition of this thesis was therefore to produce a specified suggestion of how to make a change in Electrolux Professional’s production to improve the resource, cost, and workflow efficiency directly and/or indirectly. This is done on the basis of answering two questions: 1. Is the current system improvable? 2. What kind of resources are needed to improve the efficiency in the assembly system? This thesis evaluates what kind of change of routines for picking and assembly workers (with the help of both theoretical framework and suitable solution for specifically Electrolux Professional) are needed to achieve a more efficient flow. Through the collected data, observations and unstructured interviews with the staff at Electrolux Professional, together with theoretical knowledge, important factors that need to be taken into account when implementing a more efficient work flow could be developed and thus answer the study’s question: Assuming that it is possible, with which resources/methods can the internal production system be changed to contribute to the company’s goal of making the production 50% more efficient? Several improvement suggestions were studied, including a rearrangement in the warehouse, and internal system change and even self-driving trucks. The solution that was proved to be most time and resource efficient to test and most optimal to change on short notice was a restructure in the assembly material feeding process. This could be achieved by changing the routine of the workers. By simulating a change in the daily work routines, it was proven that Electrolux Professional can use 4 fulltime workers instead of 5,5. In a long term this is quite an improvement, regarding time, money and production flow for the company.

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Mutlu, Neset. "The Design And Development Of An Online Professional Development Material For Science And Technology Teachers On Assessment And Evaluation." Phd thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12615179/index.pdf.

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The purpose of this study is to design and development of an online professional development material for science and technology teachers in order to solve their problems related with assessment and evaluation issues of constructivist learning. For this purpose, design and development research method was used in design, development and validation of this instructional tool. Research has been performed in two parts. In the first part, design and development of online professional development material was carried out. In this part, ADDIE model with rapid prototyping procedure was used in three phases. To gather science and technology teachers&rsquo
perceptions and attitudes towards prototypes, semi-structured interview schedule, Internet Tutorial Attitude Questionnaire, and a Checklist for Product Evaluation was conducted to 21 science and technology teachers in total. These data were analyzed using both qualitative and quantitative methods to reveal considerations of science and technology teachers about these prototypes and to make adjustments on these prototypes accordingly. In second part, final version of this material was evaluated. In this phase, researcher used self-efficacy questionnaire about alternative assessment and evaluation methods and a checklist for material validation. These instruments were administered both before and after use of final version of online professional development material. Descriptive data analysis was conducted to reveal differences in participants&rsquo
perceived-knowledge, beliefs, and applications about alternative assessment and evaluation methods after use of online professional development material. Research results disclosed participants&rsquo
beliefs and attitudes towards content, design and usability issues of online professional development material. Besides, validation of online professional development material revealed positive changes in participants&rsquo
perceived-knowledge, their classroom practices, self-efficacy beliefs and their perceptions about appropriateness of alternative assessment methods&rsquo
usage in classroom.

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Ogwuda, Olisanwendu Ikechukwuka. "Materials science appraisal of recycled construction materials for roadways." Thesis, Abertay University, 2007. https://rke.abertay.ac.uk/en/studentTheses/70d295b3-60d9-427e-a012-c9cc05ac83e1.

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This thesis reports on a materials science appraisal for recycled construction materials in roadways, that supports engineering decision-making. Inconsistent performance criteria for roadway materials and the variable nature of material source have prompted the need for this research. The aim of the study is to investigate the application of a materials science appraisal to recycled construction materials for use in roadways. The investigation is undertaken through a literature review of roadways, conceptual development of the materials science appraisal methodology, and demonstration of the application of the materials science appraisal to recycled construction materials; and how this supports engineering decision-making. The literature review revealed that there are numerous and proven uses of recycled and secondary materials in roadway applications but there was a lack of necessary integration of materials into categories by material-type, which can better describe behaviour in an engineering situation. Three novel fundamental material types (ceramic, metallic, and polymeric) have been described. The conceptual development of the innovative and novel materials science appraisal, based on material-type, has defined how materials science through a systematic step-by-step procedure can be used to achieve engineering sustainability in roadways and provide support in engineering decision-making. The application of the novel concept of the materials science appraisal to recycled construction materials is shown through the essence of laboratory testing. The results from the materials science appraisal, together with sensitivity analysis, give an informed engineering decision on product choice. The appraisal is novel in that it is proposing a new theory on materials science and developed a paradigm shift in the evaluation of recycled construction materials. The appraisal overcomes the absence of materials science thinking in the field of roadway engineering. The materials science appraisal is of benefit to various stakeholders (client, consultant, supplier and contractor) as it provides a method for addressing material uncertainties. A system now exists for introducing into designs and any contract the principles of the materials science appraisal that will be of great benefit to industry.

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Swedling, Daniel. "Gränslandet mellan byråkrati och profession : Samarbetet i sjukpenningärenden." Thesis, Uppsala universitet, Statsvetenskapliga institutionen, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-446684.

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Forclaz, A. "Variational methods in materials science." Thesis, University of Oxford, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249532.

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Three problems are being investigated in this thesis. The first two relate to the modelling and analysis of martensitic phase transitions, while the third is concerned with some mathematical tools used in this setting. After a short introduction (Chapter 1) and overviews of the calculus of variations and martensitic phase transformations (Chapter 2), the research part of this thesis is divided into three chapters. We show in Chapter 3 that for the two wells $\mathrm{SO}(3)U$ and $\mathrm{SO}(3)V$ to be rank-one connected, where the $3\times 3$ symmetric positive definite $U$ and $V$ have the same eigenvalues, it is necessary and sufficient that $\mathrm{det}(U-V)=0$, a result that does not hold in higher dimensions. Using this criterion and a result of Gurtin, formulae for the twinning plane and the shearing vector are obtained, which yield an extremely simple condition for the occurrence of so-called compound twins. Our results also provide a simple classification of the twinning mode of the two wells by looking at the crystallographic properties of the eigenvectors of the difference $U-V$. As an illustration, we apply our results to cubic-to-tetra gonal,tetragonal-to-monoclinic and cubic-to-monoclinic transitions. Chapter 4 focuses on the mathematical analysis of biaxial loading experiments in martensite, more particularly on how hysteresis relates to metastability. These experiments were carried out by Chu and James and their mathematical treatment was initiated by Ball, Chu and James. Experimentally it is observed that a homogeneous deformation $y_1(x)= U_1x$ is the stable state for `small' loads while $y_2(x)=U_2x$ is stable for `large' loads. A model was proposed by Ball, Chu and James which, for a certain intermediate range of loads, predicts crucially that $y_1(x)=U_1x$ remains metastable i.e., a local - as opposed to global - minimiser of the energy). This result explains convincingly the hysteresis that is observed experimentally. It is easy to get an upper bound for when metastability finishes. However, it was also noticed that this bound (the Schmid Law) may not be sharp, though this required some geometric conditions on the sample. In this chapter, we rigorously justify the Ball-Chu-James model by means of De Giorgi's $\Gamma$-convergence, establish some properties of local minimisers of the (limiting) energy and prove the metastability result mentioned above. An important part of the chapter is then devoted to establishing which geometric conditions are necessary and sufficient for the counter-example to the Schmid Law to apply. Finally, Chapter 5 investigates the structure of the solutions to the two-well problem. Restricting ourselves to the subset $K=\{H\}\cup \mathrm{SO}(2)V \subset\mathrm{SO}(2)U\cup\mathrm{SO}(2)V$ and assuming the two wells to be compatible, we let $T_1$ and $T_2$ denote the two (not necessarily distinct) twins of $H$ on $\mathrm{SO}(2)V$ and ask the following question: if $\nu_x$ is a non-trivial gradient Young measure almost everywhere supported on $K$, does its support necessarily contain a pair of rank-one connected matrices on a set of positive measure? Although we do not provide a solution for the general case, we show that this is true whenever (a) $\nu_x\equiv \nu$ is homogeneous and $\mathrm{supp}\nu\cap \mathrm{SO}(2)V$ is connected, (b) $\nu_x\equiv \nu$ is homogeneous and $T_1=T_2$ i.e., when the two wells are trivially rank-one connected) or (c) $\mathrm{supp}\nu_x \subset F$ a.e., for some finite set $F$. We also establish a more general case provided a strong `rigidity' conjecture holds.

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Rouet-Leduc, Bertrand. "Machine learning for materials science." Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/267987.

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Machine learning is a branch of artificial intelligence that uses data to automatically build inferences and models designed to generalise and make predictions. In this thesis, the use of machine learning in materials science is explored, for two different problems: the optimisation of gallium nitride optoelectronic devices, and the prediction of material failure in the setting of laboratory earthquakes. Light emitting diodes based on III-nitrides quantum wells have become ubiquitous as a light source, owing to their direct band-gap that covers UV, visible and infra-red light, and their very high quantum efficiency. This efficiency originates from most electronic transitions across the band-gap leading to the emission of a photon. At high currents however this efficiency sharply drops. In chapters 3 and 4 simulations are shown to provide an explanation for experimental results, shedding a new light on this drop of efficiency. Chapter 3 provides a simple and yet accurate model that explains the experimentally observed beneficial effect that silicon doping has on light emitting diodes. Chapter 4 provides a model for the experimentally observed detrimental effect that certain V-shaped defects have on light emitting diodes. These results pave the way for the association of simulations to detailed multi-microscopy. In the following chapters 5 to 7, it is shown that machine learning can leverage the use of device simulations, by replacing in a targeted and efficient way the very labour intensive tasks of making sure the numerical parameters of the simulations lead to convergence, and that the physical parameters reproduce experimental results. It is then shown that machine learning coupled with simulations can find optimal light emitting diodes structures, that have a greatly enhanced theoretical efficiency. These results demonstrate the power of machine learning for leveraging and automatising the exploration of device structures in simulations. Material failure is a very broad problem encountered in a variety of fields, ranging from engineering to Earth sciences. The phenomenon stems from complex and multi-scale physics, and failure experiments can provide a wealth of data that can be exploited by machine learning. In chapter 8 it is shown that by recording the acoustic waves emitted during the failure of a laboratory fault, an accurate predictive model can be built. The machine learning algorithm that is used retains the link with the physics of the experiment, and a new signal is thus discovered in the sound emitted by the fault. This new signal announces an upcoming laboratory earthquake, and is a signature of the stress state of the material. These results show that machine learning can help discover new signals in experiments where the amount of data is very large, and demonstrate a new method for the prediction of material failure.

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Hartmann, Markus. "Lattice models in materials science." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2006. http://dx.doi.org/10.18452/15432.

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In der vorliegenden Arbeit wurden drei unabhängige Problemfelder moderner biophysikalischer und materialwissenschaftlicher Forschung untersucht: Diffusion in binären Legierungen, der Umbauprozess in trabekulärem Knochen und die Voraussage mechanischer Eigenschaften, insbesonders der Biegesteifigkeit, selbstorganisierender, amphiphiler Membrane. Für alle drei Problemfelder wurden Gittermodelle gewählt, um ausgesuchte Fragestellungen zu untersuchen. Für den Fall der Diffusion in Legierungen war dies, inwieweit sich der Diffusionprozess, der sich auf atomarer Ebene als diskrete Platztäusche zwischen Atomen und Leerstellen manifestiert, auf einer größeren, makroskopischen, Ebene mit Hilfe einer kontinuumstheoretischen Theorie beschreiben lässt. Im Fall der Beschreibung des Umbauprozesses in in trabekulärem Knochen wurde die die spongiöse Architektur des Knochens auf ein Gitter abgebildet und mittels einer vereinfachten mechanischen Beschreibung die lokale Belastung in jedem Knochenelement bestimmt. Die zeitliche Entwicklung des Systems wurde mittels eines stochastischen Umbaugesetzes gesteuert, das die Wahrscheinlichkeit für Knochenan- bzw. -abbau als Funktion der lokalen Volumenänderung vorgab. Es wurde gezeigt, dass ein nicht-lineares Umbaugesetz bessere Übereinstimmung mit experimentellen Ergebnissen zeigt, als ein rein lineares. Weiters wurde das Krankheitsbild der Osteoporose untersucht und es konnte eine Unterscheidung zwischen einem normalen Alterungsprozess der Knochenstruktur und einer krankhaften Veränderung gezogen werden. Um die mechanischen Eigenschaften selbstorganisierender Membrane zu bestimmen, wurden linear elastische Federkräfte zwischen benachbarten Molekülen angenommen. Die volle elastische Matrix und daraus die gewünschten Eigenschaften wurden für unterschiedliche Zusammensetzungen der Membrane bestimmt. Es wurde gezeigt, dass die Biegesteifigkeit solcher Membrane in einem begrenzten Konzentrationsbereich um mehrere Größenordnungen variieren kann.
This thesis presents the results of investigations on three independent research topics of modern biophysical and materials science research: substitutional diffusion in binary alloys, the remodelling process in trabecular bone and the prediction of mechanical properties of self assembling, amphiphilic bilayers. The basic description of all three projects is based on lattice models, a highly successful class of models that are used in several fields of modern physics to describe physical processes. For the diffusional process in alloys, which on a microscopic scale manifests in a discrete site exchange between one atom and a neighbouring vacancy, it was investigated how this microscopic description can be reconciled with a macroscopic continuum model. For the investigations on remodelling of trabecular bone, the architecture of bone was mapped onto a lattice and the local mechanical state of each element was determined by a simplified mechanical model. A stochastic description was chosen to model the time evolution of the system, relating the probability of bone formation and resorption, respectively, to the local volume changes of the bone elements. It was shown that a non-linear remodelling law is a better candidate to describe the remodelling process in real bone than a linear one. Furthermore, applying the model to osteoporosis - a wide spread bone disease - it was shown that in the features attributed to osteoporosis one has to distinguish between normal ageing of bone''s architecture and additional changes that stem from pathological alterations in the regulatory system. A simple concept was introduced to model the mechanical properties of self-assembled membranes. The molecules forming the membrane are assumed to occupy a triangular lattice, nearest neighbours are connected by linear elastic springs. It was shown that the bending rigidity exhibits a pronounced concentration dependence, varying over orders of magnitude in a narrow concentration regime.

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Maguire, John F. "Contributions to materials science and engineering." Thesis, Ulster University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.515891.

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Stoleriu, Iulian. "Integro-differential equations in materials science." Thesis, University of Strathclyde, 2001. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21413.

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This thesis deals with nonlocal models for solid-solid phase transitions, such as ferromagnetic phase transition or phase separation in binary alloys. We discuss here, among others, nonlocal versions of the Allen-Cahn and Cahn-Hilliard equations, as well as a nonlocal version of the viscous Cahn-Hilliard equation. The analysis of these models can be motivated by the fact that their local analogues fail to be applicable when the wavelength of microstructure is very small, e. g. at the nanometre scale. Though the solutions of these nonlocal equations and those of the local versions share some common properties, we find many differences between them, which are mainly due to the lack of compactness of the semigroups generated by nonlocal equations. Directly from microscopic considerations, we derive and analyse two new types of equations. One of the equations approximately represents the dynamic Ising model with vacancy-driven dynamics, and the other one is the vacancy-driven model obtained using the Vineyard formalism. These new equations are being put forward as possible improvements of the local and nonlocal Cahn-Hilliard models, as well as of the mean-field model for the Ising model with Kawasaki dynamics.

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Schuster, Kristen M. "A Sequential Exploratory Mixed Methods Study of Carnegie Libraries and the Library Profession, 1900-1910." Thesis, University of Missouri - Columbia, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10629018.

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Andrew Carnegie’s philanthropy made it possible for thousands of communities in the United States (U.S) to build free public libraries. Contemporary scholarship in library and information science (LIS) that deals with Carnegie’s philanthropy tends to place emphasis on generalized historical ideals associated with the construction of public libraries. As a result, it often fails to critically inquire into the relationships between the work performed by librarians and assumptions about the cultural value of Carnegie libraries. This dissertation investigates broad trends in library history in order to better understand the particular experiences of fifteen Midwestern communities that built public libraries with Andrew Carnegie’s money in the first decade of 20^th century. Mixed methods research supports the synthesis of broad qualitative data with specific quantitative data, which supports assessments of primary sources in relation to scholarship about the library profession and Carnegie’s philanthropy. Comparing and contrasting findings from two distinct data sets makes it possible to discuss idiosyncrasies architectural trends and to better understand the role professional rhetoric played in their development within a specific geographic region (the Midwest).

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Jansson, Hampus. "Journalistikens professionalisering och mediernas demokratiska roll? : En studie av journalistyrket som profession." Thesis, Linnéuniversitetet, Institutionen för statsvetenskap (ST), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-65321.

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The modern environment regarding the media and its scenery has changed. Throughout time, in terms of political standpoint, the press seems to have become homogenous regarding both ownership and divergence; and while the link between politics and the press are seemingly decreasing, larger companies and corporate groups focusing primarily on economy and profit has conceivably taken over. Centrally located, enclosed by this phenomenon remain the journalists. An occupational group which in the name of democracy seems to have taken the initiative to survey and inspect society as a whole. This study aim to conceptualize how parts of this group are reflecting on their occupation, how they reflect on the media regarding its democratic value and foremost how journalists reflect on professionalized journalism in which they sustain to be working by. By examining articles of The Swedish Union of Journalist’s Journal Journalisten, which is examined using a content analysis, specifically Framing Theory and The Swedish Union of Journalist’s outset of 1972, findings suggest that the environment by which journalists are working in and their commitment to professionalized journalism appear to clash, which in terms of media as a whole make its democratic role rather uncertain.

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Al-Rashed, Wael E. R. "Kuwait's tax reformation, its alternatives and impact on a developing accounting profession." Thesis, University of Hull, 1989. http://hydra.hull.ac.uk/resources/hull:3573.

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Since the discovery of oil, Kuwait has witnessed a vast economic transition which has boosted a significant welfare state. However, in recent years the situation has changed, influencing the state budget and financial resources. The search for sources of income other than oil gave rise to the possibility of imposing taxes in a hitherto tax-free country. The 1955 tax law was applied only to foreign enterprises operating in Kuwait, and since then few attempts have been undertaken to reform it. The purpose of this study is to examine the tax alternatives available to Kuwait, which could increase state revenues, and reduce the level of inequality among the population resulting from the government land purchasing programme adopted in the early sixties. It also aims, through an empirical investigation, to reveal the potential impact of tax reformation on the development of the emerging accounting profession in Kuwait. The determination of the most appropriate tax policy for Kuwait necessitates the examination of the views of those parties most concerned, who are defined in this study as the public, foreign investors, and accounting practitioners. Accordingly, questionnaires were designed, tested, distributed and analysed to reveal attitudes towards tax reformation. In addition, interviews with concerned persons in the country, including tax legislators, officials, and authors, were conducted, so as to further examine these attitudes and other aspects of tax introduction. Based on the findings of this investigation as well as the traditional literature survey, appropriate reforms are suggested, including reformation in the legislative, administrative, and technical considerations of the tax introduction. Moreover, recommendations concerning the development of the accounting profession to accommodate the new tax era are also made, including better organisation of the profession, and its contribution to taxation in Kuwait.

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Bauer, Uwe Ph D. Massachusetts Institute of Technology. "Voltage programmable materials." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/98317.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, February 2015.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 211-223).
The physical and chemical properties of nanoscale materials derive largely from structure and composition at interfaces. The possibility to electrically modify these interfacial characteristics would provide a powerful means to control material properties. Of particular recent scientific and technological interest are metal/metal-oxide bilayers, in which properties as varied as catalytic activity, charge and spin transport, ionic exchange, mechanical behavior, thermal conductivity, and magnetism all depend sensitively on oxygen stoichiometry and defect structure at the metal/metal-oxide interface. The possibility to dynamically control interface characteristics through electric-field-induced oxygen transport and electrochemical interface reactions paves the way towards voltage control of these properties in solid-state devices. Here, we focus on ferromagnetic metal/metal-oxide bilayers that exhibit strong perpendicular magnetic anisotropy derived from interfacial oxygen hybridization. In these materials, we directly observe, in situ voltage-driven oxygen migration at room temperature and show that electrical switching of the interfacial oxidation state allows for voltage control of magnetic properties to an extent never before achieved through conventional magneto-electric coupling mechanisms. By engineering the electrode and metal-oxide layers for efficient ionic exchange and transport, we improve the response time by six orders of magnitude and switch perpendicular magnetic anisotropy at the millisecond timescale. Based on this magneto-ionic coupling mechanism we demonstrate a printer-like system to reversible pattern magnetic properties and realize a prototype nonvolatile memory device in which voltage-controlled domain wall traps facilitate electrical bit selection in a magnetic nanowire register. Moreover, we report on voltage control over electronic transport properties in the same bilayer structures and show that solid-state switching of interface oxygen chemistry provides a path towards voltage-gating the wide range of phenomena governed by metal/oxide interfaces.
by Uwe Bauer.
Ph. D.

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Bryan, David Jeffrey. "Development of a Burn-Resistant Titanium Alloy Through the Laser Deposition of Elementally Blended Powders." The Ohio State University, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=osu1391597767.

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Vempati, Vamsi Krishna. "ISOTHERMAL DEFORMATION AND MODELING OF Ti-6Al-4V." Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1341865463.

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Levkulich, Nathan Charles. "An Experimental Investigation of Residual Stress Development during Selective Laser Melting of Ti-6Al-4V." Wright State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=wright1515112797193544.

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Yang, Jianping. "Synthesis and Characterizations of Lithium Aluminum Titanium Phosphate (Li1+xAlxTi2-x(PO4)3) Solid Electrolytes for All-Solid-State Li-ion Batteries." Wright State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=wright151550285784082.

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23

Wang, Menghong. "Degradation of Photovoltaic Packaging Materials and Power Output of Photovoltaic Systems: Scaling up Materials Science with Data Science." Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case1595416965256375.

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24

López, Conesa Lluís. "Advanced TEM imaging tools for materials science." Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/395195.

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Being able to directly relate the final properties with the intimate structure provides a unique insight into the functionality of materials and devices, especially when compared to the necessarily statistical nature of the information that can be retrieved by macroscopic measurements. In particular, the scale reduction associated with the Nanoscience and Nanotechnology revolution demands characterization tools capable of reaching an unprecedented resolution, in a wide range of fields, not only for standard quality control, but in order to understand the properties of matter at the nanoscale. Going from bigger to smaller devices, but also from elemental building blocks (even atoms) to bigger assemblies, basic properties and device functionalities meet. With its ability to provide different kinds of information at a very high spatial resolution, state-of-the-art TEM and related techniques are in the core of this multidisciplinary and rapidly growing field. The first major topic is related to the assessment of local atomic ordering/disordering phenomena in functional materials. A series of rare earth niobates (RE3NbO7) will be studied in order to understand the microstructural origin of their proton conduction properties, that make them excellent candidates to be used as electrode materials in solid oxide fuel cells. Also, single crystals of the tetragonal tungsten bronze (TTB) Sr0.33Ba0.66Nb2O6 (SBN-67) will be studied by different TEM techniques in order to assess the possible short range structural and/or chemical disorder. These features are thought to be responsible for the observed macroscopic uniaxial polarization vector of the material as well as its relaxor properties. A second major topic of interest will be the phenomena taking place at interfaces. This includes the characterization of a set of LaNiO3 perovskite thin films grown on different substrates (LAO, LSAT, STO, YAO). The effect of the substrate-induced compressive/tensile strain, given by lattice mismatch, on the structure of the films will be assessed and related to the observed electric transport properties. The interfaces in a GaN/InAlN multilayered system designed as a Bragg reflector for laser cavities applications will be investigated in order to account for a lower than expected reflectivity of the devices. The presence of structural defects and the detection of intergrowth of wurtzite and zinc blende phases of GaN in thin films will be addressed. Also regarding interfaces and strain conditions, the characterization of the free surface of Nb2O5 nanorods, as a key point for their humidity sensing properties. Expanding on this, the strain state of Nb2O5 when grown on SnO2 nanowires will also be studied. The coupling of the sensing capabilities of Nb2O5 with the electrical transport properties of SnO2 is of particular interest for functional sensing devices. Therefore, defects at the interface and strain state are of capital interest in order to understand the band structure alignment of the system. Interfaces in lower dimensionality systems will also be studied, as in the case of Ag@Fe3O4 dimers for applications in magnetoplasmonics. The epitaxial quality, strain, and the possible chemical diffusion through the contact surface of the two phases of the dimer are key aspects in order to properly tailor their optical properties. The last major topic is the mapping of magnetic fields at the nanoscale. The magnetic configurations of different geometric arrangements of magnetite Fe3O4 nanocubes will be studied. This characterization is aimed at obtaining enhanced responses in magnetic hyperthermia treatments for cancer. Given the strong interrelationship between the problems under study, the chapter structure follows the dimensionality of the systems under study (3D, 2D, 1D and 0D systems).
La reducció en l'escala espacial associada a la revolució de la Nanociència i la Nanotecnologia fa necessari comptar amb una sèrie d'eines capaces d'assolir una resolució sense precedents en una gran varietat d'àress, ja no tan sols com a control de qualitat, sinó per tal d'entendre les propietats de la matèria a la nanoescala. La correlació de la configuració estructural, la composició química i les distribucions de càrrega amb les propietats funcionals és imprescindible pel disseny de nous dispositius, tant des de la perspectiva 'top down' (reducció de les dimensions dels dispositius) com de la perspectiva 'bottom up' (fabricació d'estructures complexes a partir de blocs més petits, fins i tot àtoms). La capacitat de la Microscòpia Electrònica de Transmissió (TEM) de proporcionar diferents tipus d'informació amb una alta resolució espacial, situa les tècniques avançades de TEM com a peça clau en el desenvolupament d'aquest camp multidisciplinari i creixent. L'objectiu principal d'aquesta tesi ha estat l'aplicació de tècniques quantitatives d'imatge TEM per la resolució de problemes en ciència dels materials. La tesi cobreix un espectre ampli pel que fa al tipus de materials estudiats i els seus camps d'aplicació. El Capítol 1 presenta una introducció general a la teoria de formació d'imatge aplicada a la microscopia TEM. S'hi exposen els diferents fenòmens d'interacció electró-matèria que són responsables dels diferents tipus de contrast que es poden trobar a les imatges TEM. El Capítol 2 presenta les tècniques experimentals que es faran servir en la caracterització dels materials, en concret la simulació d'imatges d'alta resolució (HRTEM), l'holografia electrònica i l'anàlisi de la fase geomètrica (GPA). S'hi pot trobar una descripció del marc teòric i dels fonaments experimentals, juntament amb un resum dels resultats més recents en aquests camps. Els resultats experimentals s'agrupen en els capítols posteriors segons la dimensionalitat dels sistemes estudiats. En ordre decreixent de dimensionalitat s'hi inclouen: materials massius (3D), capes primes (2D), nanofils (1D) i nanopartícules (1D).

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25

Osorio, Guillén Jorge Mario. "Density Functional Theory in Computational Materials Science." Doctoral thesis, Uppsala University, Department of Physics, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4496.

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The present thesis is concerned to the application of first-principles self-consistent total-energy calculations within the density functional theory on different topics in materials science.

Crystallographic phase-transitions under high-pressure has been study for TiO2, FeI2, Fe3O4, Ti, the heavy alkali metals Cs and Rb, and C3N4. A new high-pressure polymorph of TiO2 has been discovered, this new polymorph has an orthorhombic OI (Pbca) crystal structure, which is predicted theoretically for the pressure range 50 to 100 GPa. Also, the crystal structures of Cs and Rb metals have been studied under high compressions. Our results confirm the recent high-pressure experimental observations of new complex crystal structures for the Cs-III and Rb-III phases. Thus, it is now certain that the famous isostructural phase transition in Cs is rather a new crystallographic phase transition.

The elastic properties of the new superconductor MgB2 and Al-doped MgB2 have been investigated. Values of all independent elastic constants (c11, c12, c13, c33, and c55) as well as bulk moduli in the a and c directions (Ba and Bc respectively) are predicted. Our analysis suggests that the high anisotropy of the calculated elastic moduli is a strong indication that MgB2 should be rather brittle. Al doping decreases the elastic anisotropy of MgB2 in the a and c directions, but, it will not change the brittle behaviour of the material considerably.

The three most relevant battery properties, namely average voltage, energy density and specific energy, as well as the electronic structure of the Li/LixMPO4 systems, where M is either Fe, Mn, or Co have been calculated. The mixing between Fe and Mn in these materials is also examined. Our calculated values for these properties are in good agreement with recent experimental values. Further insight is gained from the electronic density of states of these materials, through which conclusions about the physical properties of the various phases are made.

The electronic and magnetic properties of the dilute magnetic semiconductor Mn-doped ZnO has been calculated. We have found that for an Mn concentration of 5.6%, the ferromagnetic configuration is energetically stable in comparison to the antiferromgnetic one. A half-metallic electronic structure is calculated by the GGA approximation, where Mn ions are in a divalent state leading to a total magnetic moment of 5 μB per Mn atom.

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26

Ghafoor, Naureen. "Materials Science of Multilayer X-ray Mirrors." Doctoral thesis, Linköpings universitet, Tunnfilmsfysik, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11343.

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This thesis treats the reflective and structural properties of multilayer structures. Soft X-ray multilayer mirrors intended as near-normal incidence reflective optics and polarizers in the water window (λ=2.4-4.4 nm) are the main focus. Such mirrors require multilayer periodicities between 1.2-2.2 nm, a large number ~600of multilayer periods (N), and atomically flat interfaces. Bi-metallic multilayers were deposited by dual-target magnetron sputtering on Si(001) Geometrical roughness and intermixing/interdiffusion at the interfaces were investigated in connection with the impact of ion-surface interactions during growth of Cr/Ti, Cr/Sc, and Ni/V multilayers. This was achieved by comparing multilayers grown with or without high-flux low energy (Eion<30 eV) ion assistance. The use of modulated ion assistance resulted in a substantial improvement of interface flatness and abruptness in each of theAb-initio calculations indicate that the stabilization of the amorphous layer structure is due to a lowering of the total energy of the system by eliminating high energy incoherent interfaces between crystalline Sc and Cr. Light element incorporation in Cr/Sc multilayers was investigated through residual gas pressure variation. It is shown that multilayers retain their structural and optical properties within the high vacuum range of 2×10-7-to-2×10-6 Torr. The incorporation of 34 at.% nitrogen at a higher residual gas pressure ( ~2×10-5 Torr) resulted in highly textured understoichiometricx/ScNy multilayers. As a result of nitrogen incorporation, interface widths as small as 0.29 nm, and near-normal incidence reflectivity enhancement (at λ=3.11 nm) by 100 % (compared to pure Cr/Sc multilayers) was achieved. Light element incorporation was also found to be advantageous for the thermal stability of the multilayers. In-situ hard X-ray reflectivity measurements performed during isothermal annealing in thex/ScNy are stable up to 350 °C. As an alternative route to metallic multilayers, single crystal CrN/ScN superlattices, grown by reactive sputtering in N atmosphere onto MgO(001), were also investigated. The superlattice synthesis at 735 °C, resulted in highly abrupt interfaces with minimal interface widths of 0.2 nm. As-deposited superlattices with only 61 periodsλ=3.11 nm as well as very high thermal stability up to 850 °C.
Denna avhandling behandlar syntes, analys, och materialvetenskap rörande så kallade multilagerspeglar för mjuk röntgenstrålning. Speglarna är lämpade som optiska komponenter för instrument såsom röntgenmikroskop i våglängdsområdet 2,4 nm till 4,4 nm, även kallat vattenfönstret. Tack vare de senaste decenniernas stora teknologiska och vetenskapliga framsteg i att framställa mycket intensiva källor för mjuk röntgenstrålning, såsom tex synkrotronljuskällor, frielektronlasrar, och plasmagenererade källor, är det nu tänkbart att utnyttja denna strålning till nya tillämpningar som tidigare inte varit möjliga. Några exempel är; röntgenmikroskopi av biologiska preparat med upplösning ca 1/100 av det som är möjligt med synligt ljus, fotolitografi av Det finns flera stora utmaningar för att lyckas tillverka multilagerspeglar. Först och främst måste man hitta materialkombinationer som ger upphov till reflektion i mellanytorna mellan materialen men som inte samtidigt absorberar all röntgenstrålning. Dessutom måste materialen gå att belägga på varandra i flera hundra tunna lager, vart och ett endast ca 1 nanometer tjockt, med en ytojämnhet om endast några tiondels nanometer. Den absoluta tjockleks precision i varje I det här arbetet har fyra olika typer av multilagerbeläggningar undersökts: krom/titan (Cr/Ti), krom/skandium (Cr/Sc), nickel/vanadin (Ni/V) samt kromnitrid/skandiumnitrid (CrN/ScN). Materialvalen har baserats på teoretiska beräkningar som visat att dessa materialsystem genererar mycket god reflektans i vattenfönstret. Varje kombination av metaller är optimal för en specifik våglängd och de individuella lagertjocklekarna måste optimeras teoretiskt för varje enskilt För Cr/Sc multilager har vi visat att lagren som beläggs har en oordnad, så kallad amorf, struktur mellan metallatomerna som har sitt ursprung i att multilagrets totala energi kan sänkas om mellanytor mellan kristallint Cr och kristallint Sc kan undvikas. Studier av effekterna av kväveupptag hos Cr/Sc multilagerspeglar under sputtringsprocessen har lett till ökad förståelse av materialsystemet. Till exempel har vi visat att kvävet framförallt binder till de inre regionerna av Sc och inte så mycket till Cr-lagren eller i mellanytorna. Med kväve i strukturen har vi gjort speglar som tål höga temperaturer, vilket är av stor betydelse för tillämpningar baserade högintensiva ljuskällor. Så kallade supergitter, dvs multilager

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27

Osorio, Guillén Jorge Mario. "Density functional theory in computational materials science /." Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4496.

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28

Kapadia, Rasesh Dilranjan. "Applications of NMR imaging in materials science." Case Western Reserve University School of Graduate Studies / OhioLINK, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=case1055794721.

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29

CARONE, FABIANI FILIPPO. "Adsorbption and scattering phenomena in materials science." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2014. http://hdl.handle.net/10281/50846.

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The present work is divided in two part. The first is dedicated to the investigation of the gas-metal interactions, an interesting area in the basic surface science but also in applied one, since it could provide a more efficient way to design corrosion-resistant structural metals. In particular, we concentrate our attention on the study H2S on Fe surface. Experimental studies, of adsorption of H2S on Fe, and first-principle calculations were carried out for these systems, clarifying some important questions, such as adsorption geometry and dissociation pathways for H2S, on the above close-packed metal surfaces. However, real samples will also include a number of defects, in particular step edges where bonding of adsorbates is usually stronger than at facets. It is therefore interesting to investigate adsorption of H2S on a stepped Fe surface, a task which has not been considered yet to the best of our knowledge. In the present work we study the H2S interaction with Fe(310) surfaces by DFT calculations in order to understand the role of step defects in the adsorption properties. We recall that the (310) surface is relatively stable, and its surface energy predicted to be even smaller than that of Fe(110). We do not only obtain the binding sites and adsorption energies of H2S and its components, but we also relate bonding to the detailed features of the localdensity of states (LDOS). The second part of the present thesis is devoted to the dynamics of scattering. Scattering underlies various physical processes in different field of physics, mainly in solid state, as for example in thermoelectricity, about the filtering of hot electrons by defects, or adsorption and desorption by a surface, or in charge injection and field emission trough interface, usually associated with tunneling mechanisms. The recent developments of nanotechnology and the advent of modern high-speed high-density MOS devices, have revived the technological and theoretical interest of the scientific community on the scattering problem and in particular on quantun tunneling mechanism usually associated. Ultrascaled nanometric CMOS compatible single electron transistors (SETs) and single atom trasistors has lead the emergence of density of states graining and fluctuations in the contacts which may determine discretization of energy levels, charge localization at intradopant length scale and selection rules on quantum states in tunnelling. Consequently, the understanding of dependence of charge dynamics, across a barrier, from the initial position constitutes a relevant aspect in such systems. In this work we study the scattering process in the non stationary framework using Gaussian wave packet (GWP) to describe the particle wave function of the system so as to consider the dependence of scattering dynamics from the initial conditions. Through a numerical solution of the Schr¨odinger equation we analyse the evolution of the system calculating the transmission of the scattering GWP as a function of the initial spread and position x(0), and comparing simulated data with theoretical results. By our analysis a new important issue emerges: the time spent by the particle to reach its asymptotic probability to be observed beyond the barrier ( that we call formation time), strongly depends on initial conditions, and in particular on x(0). Finally, to analytically express such a dependence, we propose a semi-classical approximated model in which tf is described as the time spent by a finite support (accounting for the 0.99 of the probability) of the incident wave packet to cross the barrier, namely the time required to locate, in coordinate space, the greatest amount of the GWP’s probability distribution beyond the barrier interface.

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30

Lokander, Mattias. "Performance of Magnetorheological Rubber Materials." Doctoral thesis, KTH, Fibre and Polymer Technology, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-31.

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Magnetorheological (MR) rubber materials are the solid analogue of magnetorheological fluids; i.e. their rheological properties can be controlled continously, rapidly, and reversibly by an applied magnetic field. They consist of magnetically polarisable particles in an elastomer matrix and they can be made to respond to changes in their environment; hence, they are considered as "smart" materials. Examples of potential applications for these materials are adaptive tuned vibration absorbers, stiffness-tuneable mounts and suspensions, and automotive bushings.

The purpose of this work was to increase the knowledge relating to magnetorheological materials for damping applications. The materials should exhibit a large response to an applied magnetic field, and have good mechanical and long-term properties.

MR rubber materials were made from nitrile, natural and silicone rubber, with irregularly shaped iron particles several micrometres in size. The particles were not aligned by a magnetic field prior to the vulcanisation; hence, the materials can be considered to be isotropic. These materials show a large MR effect, i.e. an increase in the shear modulus when a magnetic field is applied, although the particles are not aligned within the material. This is explained by the low critical particle volume concentration (CPVC) of such particles. Similar behaviour can be obtained with materials containing carbonyl iron, if the particles are aggregated so that they behave like large irregular particles. The iron particle concentration must be very close to the CPVC in order to obtain a large MR effect without alignment of the particles.

The absolute MR effect (MPa) in an isotropic MR rubber material with large irregular iron particles is independent of the matrix material, and the relative MR effect (%) can thus be increased by the addition of plasticisers. However, the obtainable effect is limited by the reinforcement of the particles and by friction between the particles. Therefore, it is very difficult, if not impossible, to achieve an MR effect larger than 60%.

Other ways of increasing the MR effect are to increase the strength of the magnetic field, although the materials saturate magnetically at high field strengths, or to use small strain amplitudes. The strong strain amplitude dependence of the MR effect suggests that MR rubber materials are most suitable for low amplitude applications, such as sound and vibration insulation. Measurements at frequencies within the audible frequency range show that this is a promising application for MR rubber materials.

The incorporation of large amounts of iron into the rubber matrix decreases the oxidative stability dramatically. This is probably due to iron oxides on the surface of the particles, and to the fact that the oxidation rate is enhanced by iron ions, which are able to diffuse into the matrix. Standard antioxidants do not provide sufficient stabilisation for MR rubbers. Thus, proper stabilisation systems have to be found in order for these materials to be successful in applications.

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31

Sagar, Ambuj Daya. "Materials separation by dielectrophoresis." Thesis, Massachusetts Institute of Technology, 1989. http://hdl.handle.net/1721.1/14215.

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32

Krasnow, Nicholas Riordan. "Antimicrobial Copper Iodide Materials." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/612146.

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Environmental microorganisms are implicated as the causative agents in a significant portion of healthcare associated infections (HAI) and antimicrobial resistant infections (AMR), which result in increased costs and suffering around the world. Furthermore, common environmental microorganisms participate in microbiological degradation of materials and the bio-fouling of various systems. This also results in a tremendous amount of damage in many different materials and many different sectors. The focus of this dissertation was the development of an additive that could be easily added to common materials to make them self-disinfecting and to protect them from microbial damage. The ultimate goal was to develop an additive that could be added using standard techniques and without adversely affecting the final material. Cuprous iodide (CuI) was determined to be an ideal starting material for the development of improved antimicrobial materials because of its neutral appearance and high antimicrobial activity as compared to other silver and copper materials. It was found that the antimicrobial efficacy of CuI could be amplified if prepared as a small particle and especially in the presence of vinylpyrrolidone polymers. A comminution process was then developed to produce these small particles. By using select copolymers, various CuI small particles formulation were developed to be compatible with a variety of different matrices. The efficacy of these CuI containing matrices was dependent on the compatibility of the CuI formulation with the matrix. A variety of applications were demonstrated with good antimicrobial efficacy where the particles were easily added to the finished material with minimal or no change in appearance.

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33

Malan, Mareta. "Novel materials for VOC analysis." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/71646.

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Thesis (MSc)--Stellenbosch University, 2012.
ENGLISH ABSTRACT: The need to analyse and detect volatile organic compounds (VOCs) at trace levels has led to the development of specialized sample preparation techniques. The requirement for trace analysis of VOCs stems from the negative effects they have on the environmental and human health. Methods for the analysis of non-polar VOCs commonly found as trace contaminants in water and analysis of more polar oxygenated compounds commonly found in zero-VOC water-based paints were developed. Solid phase micro extraction (SPME) was employed and extraction of the majority of the target analytes could be achieved at levels below 0.3 μg.l-1. In an attempt to further improve the detection of these two target analyte groups, novel materials based on poly(dimethyl siloxane) (PDMS) were investigated as possible extraction phases for VOCs, with the focus specifically on the analysis of the polar analytes in paint. Conventional free radical polymerization was used to synthesize poly(methyl methacrylate-graft-poly(dimethyl siloxane) (PMMA-g-PDMS), poly(methacrylic acid)-graft-poly(dimethyl siloxane) (PMAA-g-PDMS), polystyrene-graftpoly( dimethyl siloxane) (PSty-g-PDMS) and poly(butyl acrylate)-graft–poly(dimethyl siloxane) (PBA-g-PDMS). These polymers have a copolymer functionality which presents a series of different polarities. The MMA-g-PDMS and MAA-g-PDMS as well as the homopolymers were electrospun into nanofibers. The low glass transition temperature and molecular weight of the PBAg- PDMS meant that this polymer could not be electrospun. Scanning electron microscopy (SEM) was used to study the fiber morphology of the electrospun fibers and the non-beaded fibers were further investigated. Polyacrylonitrile-graft-poly(dimethyl siloxane) (PAN-g-PDMS) previously synthesized and electrospun by another member of the group were also investigated for use as possible extraction material in volatile analysis. The thermal stability of the nanofibers at 200°C was studied using thermal gravimetric analysis (TGA). This property is important since after the target analytes are extracted using the nanofibers, elevated temperatures are used to thermally desorp the volatile analytes from the extraction materials prior to GC analysis. The PAN-g-PDMS, MMA-g-PDMS and PMMA showed no significant weight loss during thermal evaluation, however, it was observed that the PMMA and PMMA-g-PDMS nanofibers looses their nanostructure and that the PAN-g-PDMS nanofibers changes colour from white to yellow to rust brown. The polymers based on MAA showed weight losses of more than 10% after one hour of exposure to the elevated temperatures, but the nanostructure remained intact. The PAN-g-PDMS, PMAA-g-PDMS and PMAA nanofibers were evaluated as possible extraction materials for VOC analysis. The nanofibers were evaluated using a similar approach to that of stir bar sorptive extraction (SBSE). Headspace sorptive extraction (HSSE) using a commercially available PDMS stir bar and the novel materials were used to evaluate the extraction efficiency of the different materials. The optimized extraction method developed using SPME were employed for the extraction using the nanofibers and PDMS stir bar. It was noted that the nanofibers lose their extraction capabilities during the first extraction/desorption cycle possibly due to thermal degradation therefore each of the materials can only be used in a single extraction. The majority of the non-polar analytes were extracted using the nanofibers at levels of 500 μg.l-1, however it was noted that the commercially available SPME extraction materials and the PDMS stir bar had superior extraction efficiencies for the specific target analytes. In the evaluation of the nanofibers for extraction of the more polar oxygenated analytes it was noted that 2-Ethylhexylacrylate was the only analyte to be extracted by all of the materials. The PAN-g-PDMS extracted three of the four analytes at levels of 100 μg.l-1. At lower analyte concentrations of 10 μg.l-1 only two of the four acrylate compounds were detected using the PAN-g-PDMS nanofibers. Ethyl acrylate was not extracted by any of the novel materials, whereas in SPME using the CAR/PDMS fiber, the LOD was determined to be below 1 μg.l-1. Although these materials were not superior to the commercially available phases, this is only the case for the specific target analytes analyzed.
AFRIKAANSE OPSOMMING: Die behoefte vir die analiese van vlugtige organiese verbindings (VOS) op spoorvlak, het gelei tot die ontwikkeling van gespesialiseerde monster voorbereidingstegnieke. Die vereiste vir die spoor analiese van die VOS het ontstaan uit die negatiewe uitwerking wat hierdie stowwe het op die omgewing en menslike gesondheid. Metodes vir die analiese van nie-polêre VOS wat algemeen voorkom as spoorkontaminante in water en polêre suurstofryke verbindings wat algemeen voorkom in nul-VOS water-gebaseerde verf was ontwikkel. Soliede fase mikro-ekstraksie (SFME) was gebruik, en die ekstraksie van die meerderheid van die teikenstowwe kon gedoen word op vlakke laer as 0,3 μg.l-1. In 'n poging om die opsporing van hierdie twee teiken analietgroepe verder te verbeter, is nuwe materiale gebaseer op polidimetielsiloksaan (PDMS), ondersoek as moontlik ekstraksiefases vir VOS, met die fokus spesifiek op die analiese van die polêre stowwe in verf. ’n Konvensionele vrye radikaal polimerisasieproses was gebruik om poli (metiel- metakrilaat)-entpoli( dimetielsiloksaan) (PMMA-g-PDMS), poli(metakrilaatsuur)-ent–poli (dimetielsiloksaan) (PMAA-g-PDMS), polistireen-ent-poli(dimetielsiloksaan) (PSty-g-PDMS) en poli(butielakrilaat)- ent-poli(dimetielsiloksaan) (PBA-g-PDMS) te sintetiseer. Hierdie ko-polimere het 'n kopolimeer funksionaliteit wat 'n reeks van verskillende polariteite bied. Die MMA-g-PDMS en MAA-g-PDMS sowel as die homopolimere was ge-elektrospin in orde om nanovesels te vorm. Die lae glasoorgangstemperatuur en molekulêre gewig van die PBA-g-PDMS het beteken dat hierdie polimeer nie elektrospin kon word nie. Skandeerelektronmikroskopie (SEM) was gebruik om die veselmorfologie van die ge-elektrospinde vesels te bestudeer en die nanovesels wat ’n eweredige oppervlak gehad het, was verder ondersoek. Poliakrilonitriel-ent-poli(dimetielsiloksaan) (PAN-g- PDMS) wat voorheen gesintetiseer en ge-elektrospin was deur 'n ander lid van die groep is ook ondersoek vir gebruik as moontlik ekstraksiemateriaal vir die analiese van vlugtige stowwe. Die termiese stabiliteit van die nanovesels was by 200°C bestudeer met behulp van ‘n termiese gravimetriese analiese (TGA) instrument. Hierdie eienskap is belangrik, aangesien die teikenstowwe by hoë temperature van die nanovesels gedesorbeer word voor die GC-analiese. Die PAN-g-PDMS, MMA-g-PDMS en PMMA het geen beduidende gewigsverlies tydens termiese evaluering gehad nie, alhoewel dit egter waargeneem was dat die PMMA en PMMA-g-PDMS nanovesels hulle nanostruktuur verloor en dat die PAN-g-PDMS nanovesels se kleur verander van wit na geel na roesbruin gedurende die termiese analiese. Die polimere wat gebaseer was op MAA het ’n gewigs-verlies van meer as 10% getoon na 'n uur van blootstelling aan die verhoogde temperature, maar die nanostruktuur het ongeskonde gebly. Die PAN-g-PDMS, PMAA-g-PDMS en PMAA nanovesels was geëvalueer as moontlike ekstraksiemateriale vir VOS-analiese. Die nanovesels was geëvalueer met 'n soortgelyke benadering tot dié van “stir bar“ sorpsie ekstraksie (SBSE). Bo-ruimte sorpsie ekstrasie is gebruik om die ekstraksie-doeltreffendheid van die verskillende materiale (kommersiële PDMS en nanovesels) te evalueer. Die geoptimaliseerde ekstraksiemetode ontwikkel in SFME was gebruik vir die ekstraksie van die VOS met die nanovesels en die PDMS “stir bar“. Dit was waargeneem dat die nanovesels hul ekstraksievermoë verloor tydens die eerste ekstraksie/desorpsie siklus, moontlik as gevolg van termiese degradasie dus, kon die materiale slegs ‘n enkele maal gebruik word vir die ekstraksie. Die meerderheid van die nie-polêre stowwe was ge-ëkstraeer deur gebruik te maak van die nanovesels op vlakke van 500 μg.l -1, maar die kommersieel beskikbare SFME ekstraksie materiale en die PDMS “stir bar“ se ekstraksie-doeltreffendheid vir die spesifieke stowwe was beter. In die evaluering van die nanovesels vir die ekstraksie van die meer polêre suurstofryke stowwe was daar waargeneem dat 2- etielheksielakrilaat die enigste analiet was wat ge-ëkstraeer was deur al die materiale. Die PAN-g- PDMS kon drie van die vier polêre stowwe op vlakke van 100 μg.l-1 opspoor. By laer analietkonsentrasies van 10 μg.l-1 kon slegs twee van die vier akrilaat verbindings opgespoor word deur gebruik te maak van hierdie nanovesels. Etielakrilaat was nie ge-ëkstraeer deur enige van die nuwe materiale nie, terwyl in SFME met die gebruik van die CAR/ PDMS vesel, die analiet op vlakke onder 1 μg.l-1 opgespoor kon word. Alhoewel hierdie nuwe materiale nie beter is as die kommersieel beskikbare ekstraksiemateriale nie is dit net die geval vir die spesifieke teiken analietgroepe wat ondersoek was in hierdie studie.

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Zhu, Fuyou. "Advanced materials for composite armour." Thesis, Queen Mary, University of London, 2009. http://qmro.qmul.ac.uk/xmlui/handle/123456789/1775.

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Composite integral armour plays an important role in future combat system. Despite numerous experimental studies there are still disadvantages such as complex manufacturing process, relatively big damage area, difficult to repair and limit shape etc. Composite integral armour without all these problems is essential for the success of future main battle tank which has a total weight of only 20 tons. 3D fabrics are seen as potential solution to poor impact damage tolerance of textile composites. Binder yarns in through-thickness direction can bridge cracks and stop crack tip growth resulting very good impact damage tolerance. The major purple of this work is to incorporate new materials and new configuration into composite integral armour. The underlying premise is that ballistic performance of new armour is judged mainly by single hit ballistic limit followed by damage resistance which in turn followed by energy absorption in high energy low velocity impact. Computer simulation of 3D textile composites and damage mechanism study were used through-out the study for analysing and explaining experimental results. Judged by these properties, conclusions regarding to ballistic performance of eight 3D texile composties were made. The benefit of the work will be a new explanation of composite armour research. This will help the success of future combat system.

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Tolley-Stokes, Rebecca, and Carol Smallwood. "Mentoring in Librarianship: Essays on Working with Adults and Students to Further the Profession." Digital Commons @ East Tennessee State University, 2011. https://dc.etsu.edu/etsu_books/196.

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An anthology by practicing academic, public, school, special librarians sharing their librarianship know-how by mentoring adults or students: personal, one-on-one contact to further librarianship. Concise, how-to chapters using bullets, headings, based on experience to help colleagues further the profession.

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Yoak, Beth A. "Rapid Nailing Method for Joining Materials." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1397604720.

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37

Nugent, Thomas J. (Thomas Joseph) 1971. "Spherical indentation of magnetostrictive materials." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/85369.

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Choi, In-Suk Ph D. Massachusetts Institute of Technology. "Indentation of plastically graded materials." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/38587.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2007.
Includes bibliographical references (p. 115-126).
The introduction of certain controlled gradients in plastic properties is known to promote resistance to the onset of damage at contact surfaces during some tribological applications. Gradients in composition, microstructure and plastic properties can also be deleterious to contact-damage resistance in some situations. In order to realize such potentially beneficial or deleterious effects of plastic property gradients in tribological applications, it is essential first to develop a comprehensive understanding of the effects of yield strength and strain hardening exponent on frictionless normal indentation. To date, however, systematic studies of plasticity gradient effects on indentation response have not been completed. A comprehensive parametric study of the mechanics of indentation of plastically graded materials is completed in this work by recourse to finite element (FE) computations. On the basis of a large number of detailed computational simulations, a general methodology for assessing instrumented indentation response of plastically graded materials is formulated so that quantitative interpretations of depth-sensing indentation experiments could be performed. The specific case of linear gradient in yield strength is explored in detail.
(cont.) The FE analysis leads to a universal dimensionless function to predict load displacement curves for plastically graded engineering materials. Experimental validation of the analysis is performed by choosing the model system of an electrodeposited nanostructured Ni-W alloy, where the plastic property variation is introduced through a linear variation in grain size with distance through the thickness. The universal dimensionless function is shown to correlate with the shield factor which is used to predict crack behavior at the interface of plastically graded materials. Here in this work a general framework is proposed for the indentation of plastically graded materials based on energetic considerations. Possible mechanisms underlying indentation size effects are also explored including the surface energy terms in the proposed energy based framework so as to rationalize a broad range of experimental observations. Practical implications of the present work are highlighted.
by In-Suk Choi.
Ph.D.

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Paramonova, Ekaterina (Ekaterina D. ). "CRUD resistant fuel cladding materials." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/82447.

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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2013.
"June 2013." Cataloged from PDF version of thesis.
Includes bibliographical references (pages 27-29).
CRUD is a term commonly used to describe deposited corrosion products that form on the surface of fuel cladding rods during the operation of Pressurized Water Reactors (PWR). CRUD has deleterious effects on reactor operation and currently, there is no effective way to mitigate its formation. The Electric Power Research Institute (EPRI) CRUD Resistant Fuel Cladding project has the objective to study the effect of different surface modifications of Zircaloy cladding on the formation of CRUD, and ultimately minimize its effects. This modification will alter the surface chemistry and therefore the CRUD formation rate. The objective of this study was to construct a pool boiling facility at atmospheric pressure and sub-cooled boiling conditions, and test a series of samples in simulated PWR water with a high concentration of nanoparticulate CRUD precursors. After testing, ZrC was the only material out of six that did not develop dark, circular spots, which are hypothesized to be the beginnings of CRUD boiling chimneys. Further testing will be needed to confirm that it is indeed more CRUD resistant, even under realistic PWR conditions in a parallel testing facility.
by Ekaterina Paramonova.
S.B.

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40

Wezenberg, Sander Johannes. "Exploring metallosalen complexes in materials science and catalysis." Doctoral thesis, Universitat Rovira i Virgili, 2011. http://hdl.handle.net/10803/37357.

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Los complejos “metalosalen” [salen = N,N’-bis(salicilideno)etilendiamina] han sido objeto de estudio en la catálisis homogénea y últimamente también en la ciencia de materiales y catálisis multimetálica. En cuanto a esto, hemos explorado el potencial de los complejos “salfen” [N,N’-bis(salicilideno) fenilendiamina] centrados en Zn(II) como componente en el desarrollo de nuevos materiales y sistemas multimetálicos. Los primeros capítulos de esta tesis proporcionan una mejor comprensión sobre las propiedades de estos complejos y esto es seguido por aplicación como detector quiral y estudios de comportamiento de autoensamblaje. Los últimos capítulos se centran en sistemas metalosalen multimetálicos mediante enfoques supramolecular y covalente para su aplicación en la catálisis cooperativa. Este tesis demuestra el potencial de los compuestos salen para su aplicación en ciencia de materiales y catálisis cooperativa.
Metallosalen complexes [salen = N,N’-bis(salicylidene)ethylenediamine] have been well-studied in homogeneous catalysis and lately reveive inceasing interest in materials science and multimetallic catalysis. In view of this, we have explored the potential of Zn(II)-centered salphen [N,N’-bis(salicylidene)phenylenediamine] complexes as a building block in the development of new materials and multimetallic systems. The first chapters of this thesis provide a better understanding of the properties of these complexes and this is followed by application as a chiral sensor and studies of their self-assembly behavior. The last chapters focus on multimetallic metallosalen systems for application in cooperative catalysis using supramolecular and covalent approaches. This thesis illustrates the potential of metallosalen complexes for application in materials science and cooperative catalysis

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Nordborg, Anna. "Synthesis and modifications of materials for separation science." Doctoral thesis, Umeå : Department of Chemistry, Umeå University, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1572.

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42

Zhu, Bocheng. "Surface initiated polymerisation for applications in materials science." Thesis, Loughborough University, 2012. https://dspace.lboro.ac.uk/2134/10858.

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A systematic study of the surface-initiated polymerisation kinetics of a relatively new type of atom transfer radical polymerisation (ATRP), activators regenerated by electron transfer (ARGET) ATRP, is first demonstrated in this report. Poly(2-hydroxyethyl methacrylate) (PHEMA) and poly(methyl methacrylate) (PMMA) were successfully grown from silicon surfaces at room temperature by surface-initiated ARGET ATRP using a "3rd generation" cationic macroinitiator. The polymer films were analysed by ellipsometry, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). With the initial experiment showing that water accelerated conventional ATRP but made it less controlled, the effect of solvent on ARGET ATRP was also evaluated. The living character of ARGET ATRP was demonstrated by successfully reinitiating PHEMA-grafted silicon wafers to grow a second block of PHEMA. Initiator density was shown to have a great effect on the growth rate of PHEMA film thickness on silicon surfaces by comparing the ARGET ATRP growth of PHEMA films using two different initiators, "1st generation" and "3rd generation" cationic macroinitiators, which have different ratios of initiating groups to positive charge. Another type of initiator for ATRP systems, an amide silane, was then investigated as an alternative to polyelectrolyte macroinitiators to avoid degrafting. The effects of solvent, 2, 2′ bipyridyl (bpy) ligand concentration and different types of reducing agent on the growth of PHEMA film from amide-initiator coated silicon wafers by ARGET ATRP were then explored at room temperature. However, it was found that the swings in the uncontrolled laboratory ambient temperature caused inter-sample and inter-experiment variability and so could make the evaluations inaccurate or even wrong. An investigation of temperature on ARGET ATRP showed a dramatic effect on the polymerisation rate. The higher the temperature, the faster the polymerisation proceeded. Therefore, the effects of solvent, ratio of bpy to Cu and reducing agent on the ARGET ATRP growth of PHEMA brushes from amide initiator-coated silicon wafers were re-evaluated at a constant temperature, 30 °C. The development of a polydopamine-based initiator, which was designed to be able to be immobilised on a wide range of surfaces, is then presented in this report. Polydopamine was first shown to be able to deposit on various types of material surfaces by oxidative polymerisation in aqueous solution. Bromoester initiating groups for ATRP systems were incorporated into polydopamine coatings by reacting a fraction of the dopamine monomer with 2-bromoisobutyryl bromide (BIBB) before polymerisation. The modified polydopamine initiator film grew at a comparable rate to unmodified polydopamine, with a 45 nm being grown in 24 hours. Successful incorporation of initiator groups was confirmed by XPS and FTIR, and by the growth of PMMA and PHEMA polymer brushes by ARGET ATRP from the polydopamine initiator coatings. A PMMA brush with a thickness of 239 nm was grown in 72 hours, indicating that the grafting density is sufficiently high to be in the brush regime. This initiator was demonstrated to be able to deposit on a range of substrates, such as metals (steel) and polymers (polystyrene), and successfully initiate polymer growth, demonstrating its broad applicability. The assessment of ARGET ATRP as a simple and effective tool for interfacial shear strength improvement in cellulose-based fibre reinforced thermoplastic composites is finally presented. It was demonstrated by control experiments that grafting polystyrene on glass fibre surfaces via ARGET ATRP greatly improved the interfacial adhesion between glass fibres and a high-impact polystyrene (HIPS) matrix, although a specific value of interfacial strength was not obtained due to failure of the modified glass fibre composite samples in areas other than the interface. It was then demonstrated that PMMA was successfully grown from the surfaces of polydopamine initiator coated cotton fibre and BIBB-modified cotton fibre by ARGET ATRP. Polydopamine initiator was shown to be a better initiator for cotton fibre than BIBB, possibly since the adsorbed water on cotton fibres can react with BIBB. The improvement of interfacial adhesion between cotton fibres and a PMMA matrix by grafting PMMA on the cotton surface was assessed by peel testing of cotton fibres pressed into PMMA sheets. There is a clear trend in the relationship between the peeling force and growth time of PMMA on the cotton fibre by ARGET ATRP, although the inter-sample reproducibility is not good.

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43

Boyaval, Sébastien. "Mathematical modelling and numerical simulation in materials science." Phd thesis, Université Paris-Est, 2009. http://tel.archives-ouvertes.fr/tel-00499254.

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In a first part, we study numerical schemes using the finite-element method to discretize the Oldroyd-B system of equations, modelling a viscoelastic fluid under no flow boundary condition in a 2- or 3- dimensional bounded domain. The goal is to get schemes which are stable in the sense that they dissipate a free-energy, mimicking that way thermodynamical properties of dissipation similar to those actually identified for smooth solutions of the continuous model. This study adds to numerous previous ones about the instabilities observed in the numerical simulations of viscoelastic fluids (in particular those known as High Weissenberg Number Problems). To our knowledge, this is the first study that rigorously considers the numerical stability in the sense of an energy dissipation for Galerkin discretizations. In a second part, we adapt and use ideas of a numerical method initially developped in the works of Y. Maday, A.T. Patera et al., the reduced-basis method, in order to efficiently simulate some multiscale models. The principle is to numerically approximate each element of a parametrized family of complicate objects in a Hilbert space through the closest linear combination within the best linear subspace spanned by a few elementswell chosen inside the same parametrized family. We apply this principle to numerical problems linked : to the numerical homogenization of second-order elliptic equations, with two-scale oscillating diffusion coefficients, then ; to the propagation of uncertainty (computations of the mean and the variance) in an elliptic problem with stochastic coefficients (a bounded stochastic field in a boundary condition of third type), last ; to the Monte-Carlo computation of the expectations of numerous parametrized random variables, in particular functionals of parametrized Itô stochastic processes close to what is encountered in micro-macro models of polymeric fluids, with a control variate to reduce its variance. In each application, the goal of the reduced-basis approach is to speed up the computations without any loss of precision

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Accanoor, Kalyani. "An Overview of the Subject Gateway: Materials Science." Information and Library Network Centre, An IUC of University Grants Commission, Ahmedabad - 380 009, Gujarat (INDIA), 2003. http://hdl.handle.net/10150/105918.

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The primary objective and functions of libraries have not changed due to computerization. Only, the tools and techniques to achieve these objectives with ease and accuracy have. In the present day the focus is on Electronic Information. Thus it is not only acquiring, sources of information but providing access to information and sharing also. With the Internet, WWW and Information explosion, identification and extraction of information resources is an essential function of all libraries and information centers. The Electronic information sources are rapidly growing and with a wide variety in form and content it takes a lot of time to get the required information. There is thus a need to organize and classify this wide spectrum of information. With this as background, the author has created a web page providing information to not only the internal sources at the Central Library, I.I.T Bombay but also links to external electronic information sources in the field Materials Science.

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45

Hopkins, Noel Paul. "Abradable coatings : from black art, to materials science." Thesis, Swansea University, 2007. https://cronfa.swan.ac.uk/Record/cronfa42844.

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Suck, squeeze, bang, blow! The efficiency and performance of a gas turbine engine relies on the ability to maintain high gas pressure ratios, throughout each stage of the compressor. To do this, engine manufacturers must minimise gas leakage over compressor blade and seal fin tips. Increasing the efficiency of the gas turbine engine is an area of enormous importance to engine manufacturers worldwide. The rewards are obvious when it is considered that a modest improvement of 0.5 to 1% to the Specific Fuel Consumption (SFC) can translate to huge savings on fuel costs. One way in which engine manufacturers are looking to do this is through the use of abradable seals, which are used to help seal the engine and reduce air leakage over blade tips. In an attempt to gain a fundamental understanding of abradable materials, this thesis discusses research carried out as part of an Engineering Doctorate. The research focuses on three key topic areas, identified as necessary for generating a robust understanding of the complete coating life. The research carried out within this EngD programme has helped to generate a fundamental understanding of abradable materials by focusing on three key topic areas: i) Development of Test Methodology ii) Definition of Performance Drivers iii) Implementation of Technology Within these topic areas programmes of work have been carried out, which aim to fill gaps in current knowledge and provide the knowledge and techniques for future coating development. Significant advances have been made in all aspects of abradable understanding and the knowledge generated is now being successfully implemented within the Rolls-Royce Abradable Strategy. As the demands from regulators and airlines for greater aero engine performance increase, the need for reliable and effective compressor sealing will become evermore critical. The knowledge and techniques developed within this EngD programme will enable further detailed understanding of the science of abradable materials.

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Bowerbank, Pat. "The strategic development of a health care organisation : a longitudinal study of the South African physiotherapy profession, 1971 to 2000." Doctoral thesis, University of Cape Town, 2003. http://hdl.handle.net/11427/22077.

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Bibliography: pages 147-155.
This research focuses specifically on the South African physiotherapy profession, that societal institution which is primarily concerned with health, illness and the physical elements of movement In the human body. Together with South African society as a whole this Institution has experienced monumental changes over the last 30 years. The objective of this research is to describe and critically evaluate the nature, direction and depth of those changes for the South African physiotherapy profession. To this end the research attempts to Identify some of the broad political and societal trends in the macroenvironment, and to contextualise these within the healthcare environment and the physiotherapy profession. The main argument is that social circumstances determine not only the health of the population, but also the health care services and how health care professionals function In society (Benatar, 1997). Health care services and how health care professional's function in society are socially constructed phenomena and therefore there are marked differences in the way health care is delivered from country to country and one political system to another. Over the past decade, management research has increasingly paid attention to the manner in which organisations work to Influence and shape their environments (Lawrence, 1999). A central Issue has become the manner in which organisational environments are constituted, reproduced and transformed through organisational action and relationships.

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Ivey, Dorothy Lyle. "Attitudes towards the library and information profession among practising librarians and information workers in the Western Cape." Master's thesis, University of Cape Town, 1986. http://hdl.handle.net/11427/15825.

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Bibliography: pages 237-246.
An investigation was undertaken into the attitudes held by library/information workers towards their profession because it was considered that the strength of these attitudes may affect not only the self-concept and work performance of individuals, but also the quality and dimensions of the support received by the profession from society. The study was conducted in two parts: the literature survey and the empirical investigation. The empirical investigation was limited geographically to the Western Cape region of South Africa.

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Jain, Anubhav Ph D. Massachusetts Institute of Technology. "The Materials genome : rapid materials screening for renewable energy using high-throughput density functional theory." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/69789.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2011.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 204-211).
This thesis relates to the emerging field of high-throughput density functional theory (DFT) computation for materials design and optimization. Although highthroughput DFT is a promising new method for materials discovery, its practical implementation can be difficult. This thesis describes in detail a software infrastructure used to perform over 80,000 DFT computations. Accurately calculating total energies of diverse chemistries is an ongoing effort in the electronic structure community. We describe a method of mixing total energy calculations from different energy functionals (e.g., GGA and GGA+U) so that highthroughput calculations can be more accurately applied over a wide chemical space. Having described methods to perform accurate and rapid DFT calculations, we move next to applications. A first application relates to finding sorbents for Hg gas removal for Integrated Gas Combined Cycle (IGCC) power plants. We demonstrate that rapid computations of amalgamation and oxidation energies can identify the most promising metal sorbents from a candidate list. In the future, more extensive candidate lists might be tested. A second application relates to the design and understanding of Li ion battery cathodes. We compute some properties of about 15,000 virtual cathode materials to identify a new cathode chemistry, Li₉V₃(P₂O₇)₃(PO₄)₂ . This mixed diphosphate-phosphate material was recently synthesized by both our research group and by an outside group. We perform an in-depth computational study of Li₉V₃(P₂O₇)₃(PO₄)₂ and suggest Mo doping as an avenue for its improvement. A major concern for Li ion battery cathodes is safety with respect to 02 release. By examining our large data set of computations on cathode materials, we show that i) safety roughly decreases with increasing voltage and ii) for a given redox couple, polyanion groups reduce safety. These results suggest important limitations for researchers designing high-voltage cathodes. Finally, this thesis describes the beginnings of a highly collaborative 'Materials Genome' web resource to share our calculated results with the general materials community. Through the Materials Genome, we expect that the work presented in this thesis will not only contribute to the applications discussed herein, but help make high-throughput computations accessible to the broader materials community.
by Anubhav Jain.
Ph.D.

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49

Tsai, Tsung-hsun 1961. "Hydrodynamical instability of the mushy layer during directional solidification of ammonium chloride solution in a Hele-Shaw cell." Diss., The University of Arizona, 1996. http://hdl.handle.net/10150/282278.

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Abstract:

Experiments of directional solidification in a Hele-Shaw cell, 240 mm x 245 mm x 1 mm, were carried out to study the effects of convective flows and the evolution of structure in the "mushy layer", consisting of fluid and crystallites. Three different concentrations of ammonium chloride (NH₄Cl) solution, 26%, 27% and 28%, with a constant bottom cooling temperature ranging from 5°C to -20°C were used as an analogue model for metallic alloy systems. The experimental design included techniques using Peltier heat pumps along with PID feedback control for temperature regulation. A shadowgraphic visualization method made possible the simultaneous observation of the evolution of convection in the liquid region and the phenomena of chimney formation within the mushy layer. More than one hundred runs were carried out. Temperature information and simultaneously acquired digital images were recorded automatically. The time evolution of the solidification process was traced by image processing technique from the digital images. Results show that the phenomenon of intermittent plumes frequently occurs. The number of plumes near the liquid-mush interface decreases from a larger number in the beginning to about the same number of high plumes in the liquid region or chimneys in the mush. The number of chimneys is more static than that of plumes due to the relatively low speed of solidification or dissolution. The mush consists of three different layers. A thin layer of generally upward oriented crystal forms rapidly in the beginning, followed by a second layer aggregate gradually covering it. Finally a third layer of dendritic crystals dominates the top of the growing mush. Preliminary experiments in a Hele-Shaw cell inclined at 21 degrees caused the mush structures to develop differently than in the normal geometry. The significant differences include the dendritic crystal form, the lacunae of the mush, the shape of the chimneys, and the porosity changes of the structures. Directions for future research are suggested.

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50

Hall, Abraham. "Using Freebase, an Automatically Generated Dictionary, and a Classifier to Identify a Person's Profession in Tweets." Master's thesis, University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5788.

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Abstract:

Algorithms for classifying pre-tagged person entities in tweets into one of eight profession categories are presented. A classifier using a semi-supervised learning algorithm that takes into consideration the local context surrounding the entity in the tweet, hash tag information, and topic signature scores is described. In addition to the classifier, this research investigates two dictionaries containing the professions of persons. These two dictionaries are used in their own classification algorithms which are independent of the classifier. The method for creating the first dictionary dynamically from the web and the algorithm that accesses this dictionary to classify a person into one of the eight profession categories are explained next. The second dictionary is freebase, an openly available online database that is maintained by its online community. The algorithm that uses freebase for classifying a person into one of the eight professions is described. The results also show that classifications made using the automated constructed dictionary, freebase, or the classifier are all moderately successful. The results also show that classifications made with the automated constructed person dictionary are slightly more accurate than classifications made using freebase. Various hybrid methods, combining the classifier and the two dictionaries are also explained. The results of those hybrid methods show significant improvement over any of the individual methods.
M.S.
Masters
Electrical Engineering and Computer Science
Engineering and Computer Science
Computer Science

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Dissertations / Theses on the topic 'Materials science as a profession'

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